WHEN WAS REVELATION WRITTEN?

Evidence for the early date: 70 A.D.

The many "coming soon" and "at hand" passages (1:1, 2:16, 3:11, 22:6-20) only make sense if events matching the symbolism of Revelation were not too far in the future. The Jewish themes would make no sense after 70 A.D. - there was nothing left of the Jewish state.
The Beast (which most if not all scholars agree represents Rome) was ruled by its 6th head ("head" = "king" see: 17:10) which was already in existence in John's day. Of the 7 heads (kings) only one was left - by 95 A.D. Rome was long past its 7th Caesar.
A 2nd Century manuscript of Revelation says it was written when Nero was Caesar (68 A.D.).
There were still Judaizers in the church at that time (Rev. 2:9, 3:9) - impossible after 70A.D.
The temple is apparently still standing in chapter 11.
If the temple had already been destroyed, one would expect at least one mention of it somewhere.
Revelation 2:2 shows that there were other apostles around - yet it is believed that all but John were dead by 70 A.D.
Irenaeus' statement regarding Domitian's reign is difficult to interpret and based on a secondary source. In the same passage he also mentions "ancient copies" of Revelation in existence which makes little sense if they were only a few years old.
Evidence for a massive persecution by Domitian (81-96 A.D.) is lacking.
The only time there were only 7 churches in Asia was the early 60's.
John was told he must prophesy again before kings (10:11) . . . he would have been over 90 if the late date is correct. Stories of his actions after being released from Patmos are difficult to reconcile with an aged man.

I personally find this following point most convincing: John's day must have been "the time of the end", since Daniel was told to seal the book until the time of the end, and John was told to not seal it since the time was AT HAND.

Daniel 12:4 KJV But thou, O Daniel, shut up the words, and seal the book, even to the time of the end: many shall run to and fro, and knowledge shall be increased. Daniel 12:8-9 KJV And I heard, but I understood not: then said I, O my Lord, what shall be the end of these things? (9) And he said, Go thy way, Daniel: for the words are closed up and sealed till the time of the end. Revelation 22:10 KJV And he saith unto me, Seal not the sayings of the prophecy of this book: for the time is at hand. Some have said the END BEGAN in John's day and has continued til now. That makes the entire reference in Daniel a mockery. Are they telling us that Daniel lived only 400 years before John, and could not be let in on the meanings of the visions, while the end began in John's day and stretches 5 times more than the time between Dan and John?

If John's day was "the time of the end", then that means the visions of Daniel and John would come to pass shortly ahead in time from John's day of writing of them. There were no other cataclysmic events around John's time except for the destruction of Jerusalem. This would demand Revelation was written before AD70.